Long-term weathering behavior of UV-curable clearcoats: Depth profiling of photooxidation,UVA, and HALS distributions

The long-term weathering performance of two UV-curable clearcoat systems was studied using in-plane microtomy in combination with infrared spectroscopy, UV spectroscopy, and ESR spectroscopy. Oxygen transport characteristics were also studied using the half-time method. The photooxidation versus depth profile was highly dependant on the presence of hindered amine light stabilizers (HALS) for both coating systems. Ultraviolet light absorbers (UVA) had little effect on the photooxidation profile. A photooxidation gradient was formed in both clearcoats due to a reduction in oxygen solubility when compared to standard thermoset clearcoats. This gradient was only seen in formulations not containing HALS. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

聚甲醛的光稳定化研究

采用了二苯甲酮类和苯并三唑类紫外线吸收剂(UVA)、位阻胺类光稳定剂(HALS)以及光屏蔽剂对聚甲醛进行光稳定化改性,对比了改性前后聚甲醛光降解后的物理力学性能及表面层分子量保持率。结果表明,0 5%的UVA可以显著提高POM的耐紫外光性能,苯并三唑类效果优于二苯甲酮类UVA。在酚类抗氧剂存在下,低含量的HALS(<0 25%)对聚甲醛没有光稳定化作用。     

+UVA treatment increases the degree of unsaturation in microalgal fatty acids and total carotenoid content in Nitzschia closterium (Bacillariophyceae) and Isochrysis zhangjiangensis (Chrysophyceae)

The production of metabolites by microalgae is affected by environmental conditions in which they are living. The metabolic responses of two marine microalgae, Nitzschia closterium and Isochrysis zhangjiangensis, to a 3-day UVA-stress and 3-day UVA-recovery treatment were compared, based on their growth, fatty acid profiles and content of total carotenoids. When cultured under photosynthetically active radiation, coupled with UVA treatment, both microalgae underwent a significant increase in their growth during the UVA-recovery period compared to the control. The proportions of polyunsaturated fatty acids, including linoleic acid and eicosapentaenoic acid, as well as total carotenoids, were significantly increased in both microalgae, mainly in the UVA-stress period, but not the UVA-recovery period. The metabolic responses of the two microalgae to UVA treatment were species-dependent and could be utilised to produce microalgal biomass rich in polyunsaturated fatty acids and carotenoids for use as functional food ingredients.     

基于成像传感器特性的侦察无人机航迹规划研究

针对携带成像传感器的侦察无人机的航迹规划问题,提出整体与局部航迹规划结合的方法;将侦察无人机航迹规划问题分解为两步:第一步,利用遗传算法全局搜索的优势对蚁群算法初始信息素过低进行改进,对无人机进行整体航迹规划;第二步,利用几何限制原则结合侦察无人机携带的成像传感器的特点进行局部航迹再规划;通过按照该方法规划出侦察无人机的航迹并取得较好效果的一个实例证明,该方法计算简化、贴合实际、针对性强,可为实际战场侦察无人机航迹规划提供了参考.     

Selection of NF membrane to improve quality of chemically treated surface water

The requirement for higher quality drinking water necessitates the application of more efficient water treatment techniques. Nanofiltration is one promising option for enhanced water treatment, for example, in enhanced organic matter removal. The characteristics of different nanofiltration membranes vary remarkably, and the selection of a membrane has to be made according to the requirements of an application. In this study six nanofiltration membranes (NF70, NF255, NTR-7450, NTR-7410, Desal-5 and TFC-S) were evaluated in improving the quality of chemically pre-treated surface water in a pilot-scale process. The results indicate that the membrane with high organics removal and slightly reduced ion removal characteristics (NF255) performed best in terms of product water quality as well as membrane productivity and fouling. The most permeable membrane (NTR-7410) suffered intensive fouling and insufficient product water quality. An interesting finding was that the permeates of all the tested membranes possessed a significant potential for microbial growth, despite the low nutrient contents.     

防晒化妆品UVA区效果评价方法的研究

UVA能够穿透表皮直接损伤真皮层，使皮肤老化，纤维变性，诱发皮肤癌，如何评价防晒化妆品在UVA区的防护效果，国内尚缺乏检测方法。文章介绍了体内实验及体外实验的评价方法，体内实验采用MX16黑色素－红斑－指数仪测试人的皮肤受到UVA照射后即时变成的一次性的灰我或棕色的光化学反应。这种着色称为黑化。体外实验为紫外分光光度计测试320nm-400nm的吸光度值。两个方法显示了较好的相关性，体外方法具有操作简便，快速和重复性好等特点，可以代替代内方法。     

无人机飞行控制地面仿真

针对某型无人机飞行设计要求,对无人机空中飞行进行模拟仿真,并综合测试仿真状态下的控制律运行情况。根据仿真试验的目的和要求,搭建适合无人机半实物仿真系统,介绍半实物仿真系统的组成;设计无人机的基本控制规律和逻辑,在此基础上建立某型无人机的简化数学模型,确定相关模型参数;对飞行控制系统进行仿真,构造某型无人机半实物仿真系统,并对无人机全飞行控制双机进行仿真试验、分析。试验结果表明:无人机飞行控制系统具有良好的控制效果,满足飞行控制要求。     

Improvement of gel properties of mackerel mince by phlorotannin extracts from sporophyll of Undaria pinnatifidai and UVA induced cross-linking

The effects of phlorotannin extracts (PTE) (from sporophyll of Undaria pinnatifida) added at different concentration (0, 1.6, 8, and 40 mg/g protein) with and without ultraviolet A (UVA) irradiation treatment on gel properties of mackerel (Scomberomorus niphonius) mince (MM) were investigated. The results indicated that both the breaking force and water-holding capacity (WHC) of the MM gel increased with addition of PTE, and the highest breaking force and WHC were observed with 40 mg/g PTE under UVA irradiation. Low-field nuclear magnetic resonance revealed that free water significantly decreased in this PTE-MM gel as well. UVA irradiation treatment led to reduction of total sulfhydryls and free amines in the PTE-MM gel, indicating more cross-linking between proteins. Electrophoresis results indicated that myosin heavy chains were aggregated in the UVA-treated PTE-MM gel. The microstructure of the UVA-treated PTE-MM gel showed that protein formed more evenly distributed cross-linked structures and was more compact than the untreated control gel. As a conclusion, PTE addition with UVA irradiation is shown to improve gelling properties of mackerel mince.     

竹叶黄酮在护肤品中防晒功效的初步评价

考察竹叶黄酮对紫外线辐射的防护效能。将竹叶黄酮添加到基质霜膏中制得护肤霜,采用紫外分光光度法,以紫外吸收值(透光率)为指标,对护肤霜的防晒效果进行评价。结果表明,在测试时间内,含竹叶黄酮1.0%和2.0%的护肤霜都能有效抵抗UVB辐射,按照布特星级分类标示,对UVA辐射的防护可达到三星级。竹叶黄酮可作为护肤品中的防晒功能添加剂。